This invention realtes generally to article handling apparatus and more particularly to a locking tong for securely grasping variable size, fireplace or furnace fuel.
In order to obtain heat from a fireplace or furnace, it is necessary to continuously move fuel from a supply area to the fireplace or furnace and to arrange the fuel in the fireplace or furnace for efficient burning. It is essential in moving or arranging the fuel that there be a sure grip between the fuel and holding tool. Often, fireplace fuel, such as wood, tends to be of variable size and heavy.
One type of prior art tool requires that a constant pressure be exerted by the user directly on the fuel load in order to maintain a tight grip by the tool. The requirement of applying constant pressure can be physically tiring to the user. U.S. Pat. Nos. 824,642, 1,313,788, 1,526,517, 1,884,541 and 2,429,046 disclose this type of tool.
Another type of prior art tool is incapable of handling fuel of a wide range of sizes with a sure grip. For example, U.S. Pat. No. 1,976,977 discloses a tool having a pivotal conection between its fuel-gripping members. This pivotal connection limits the size of the fuel which can be held between the members.
A third type of tool uses a spring to bias the gripping members together and requires force by the user to overcome the spring force to open the gripping members. Since spring tension decreases with use, however, slipping of the load between the gripping members eventually occurs. Furthermore, this type of tool requires the user to exert a substantial force against the spring to separate the normally closed gripping members. Exemplary of this type of prior art tool are U.S. Pat. Nos. 1,254,765, 1,857,841 and 1,976,977.
In U.S. Pat. No. 1,021,290, a fireplace fuel gripper uses rack and pinion assembly for mechanically exerting a gripping force between pairs of holding tines. This tool will not provide a sure grip over long use since wear may eventually produce slippage in the assembly resulting in uncertain gripping of the load. Furthermore, the length of the rack limits the size of the load which can be securely held.
Additionally, other prior art tools of which I am aware are difficient in that some do not provide any mechanical advantage to reduce the force which the user must exert to maintain a secure grip on the load and others are difficult to manufacture.